DBA_HIST_MEMORY_TARGET_ADVICE displays memory target advice history. This view contains snapshots of V$MEMORY_TARGET_ADVICE.
| Column | Datatype | NULL | Description | 
|---|---|---|---|
| SNAP_ID | NUMBER | NOT NULL | Unique snapshot ID | 
| DBID | NUMBER | NOT NULL | Database ID for the snapshot | 
| INSTANCE_NUMBER | NUMBER | NOT NULL | Instance number for the snapshot | 
| MEMORY_SIZE | NUMBER | NOT NULL | If the MEMORY_SIZE_FACTORcolumn has a value of 1, then this column shows the current size of memory, as set by theMEMORY_TARGETinitialization parameter.If the value of the  | 
| MEMORY_SIZE_FACTOR | NUMBER | A multiplier for the current memory size. Possible values are 0.25, 0.5, 0.75, 1, 1.5, 1.75 and 2. This multiplier times the current memory size equals the value of the MEMORY_SIZEcolumn. | |
| ESTD_DB_TIME | NUMBER | For current memory size ( MEMORY_SIZE_FACTOR = 1), the amount of database time required to complete the current workload. For a proposed memory size, the estimated amount of database time that would be required if theMEMORY_TARGETparameter were changed to the proposed size. | |
| ESTD_DB_TIME_FACTOR | NUMBER | For a proposed memory size, ratio of estimated database time to current database time | |
| VERSION | NUMBER | Version number of this recommendation |